1. Field of the Invention
This invention relates to communication systems, and more particularly, this invention relates to communication systems which provide both power and data through two conductors.
2. Description of the Prior Art
Various communication systems are known in the prior art. Some of the systems are utilized to connect computers together over a coaxial cable. An example of this type of system is the Ethernet system by the Xerox Corporation. This system utilizes a chain of repeaters to provide connections between long lengths of coaxial cable. The various systems utilized are polling of the various computers by a particular computer by an addressing system to determine if each computer has information to send. This technique is generally known as the aloha system. Another system is to provide a specific time interval based on a common system clock during which each of the computers can transmit. Various other systems, are known, for example, a computer generates a particular code onto the common network when it is ready to transmit. If the network is clear, the computer then commences to transmit. However, various interferences can and do occur in such systems. All of these systems require a high level of overhead and are generally not suitable for a low cost home environment.
None of the prior construction shows a two wire system which provides both power and data through the two conductors from a master controller to at least one subcontroller.